The present invention relates to a check chip for performing an operative validation of a sensor measuring device for assaying a specified component in a liquid sample, and more particularly, to a check chip which can be easily distinguished from a sensor having a similar shape, which is employed in the sensor measuring device, by a visually handicapped user or a weak-sighted person.
In recent years, a low-priced sensor for assaying a specified component in a liquid and a measuring device exclusively employed for reading a quantitative change in the specified component within the sensor have been developed and adopted in the clinical field.
For example, when it is cited as an example that the measuring object is glucose, there are proposed a disposable sensor for detecting an electrochemical potential difference, which comprises a specific catalysis of an enzyme and an electrode, and a measuring device exclusively employed for reading a quantitative change within the sensor, so that diabetic patients can measure and control blood sugar levels by themselves. Further, in a case where the measuring object is potassium ion or sodium ion, there are proposed a disposable ion selective electrode sensor for assaying ions in a liquid, which comprises an ion selecting film and a reference electrode, and a measuring device exclusively employed for reading a quantitative change within the sensor. As a principle applied to these disposable sensors, there is optical measurement besides the above-described electrochemical reaction.
Further, there is a measuring device which announces the measurement result of blood sugar level or ion concentration which is measured as described above, by voice or the like, whereby a visually handicapped user or a weak-sighted person can use the device with no difficulties.
As a disposable sensor which comprises a specific catalysis of an enzyme and an electrode, there is a sensor disclosed in Japanese Published Patent Application No. Sho. 61-294351. This sensor is constituted by forming electrode circuitry on an insulating plate with a printing method, and covering the electrode circuitry with madreporic body containing an oxidation-reduction enzyme and an election acceptor, thereby to integrate the whole with a cover. Therefore, the component in the biological sample can be measured as a substrate by appropriately selecting the type of the oxidation-reduction enzyme contained in the madreporic body. When a sample is applied to the sensor, the electron acceptor is deoxidized by the enzyme reaction. At this time, a predetermined voltage is applied to the electrode circuitry, whereby the deoxidized electron acceptor is oxidized electrochemically by the voltage, oxidation current flows between electrodes, and the substrate component concentration in the sample can be measured from the oxidation current value.
Further, an ion selective electrode sensor generally comprising a reference electrode, an electrolyte layer, and an ion selective film is disclosed in Japanese Examined Patent Application No. 58-4981. The disclosed ion selective electrode is constituted by depositing a metal layer on a plastic film, and coating or laying the electrolyte layer and the ion selective film thereon.
Further, a sensor and a sensor measuring device employing optical detection as a principle are disclosed in Japanese Published Patent Application No. Hei. 4-188065. This sensor, which employs optical detection as a principle, has a capillary tube shape, a part of which has optical penetrability. A dry reagent is applied in the capillary tube, and the sensor measuring device optically measures a change in color tone which is generated when the liquid sample and the reagent, which are introduced into the capillary tube, react to each other, through the optical penetrability portion, to calculate the concentration of a specific component contained in the liquid according to the color tone.
Further, when a diabetic patient measures sugar level by himself using the above-described sensor and measuring device for the sensor, a device and a method by which the patient can easily perform calibration or certification of the measuring device are disclosed in Japanese Examined Patent Application No. Hei. 8-20412. To be specific, the sensor and the measuring device utilize the fact that the resistance value of the sensor decreases sharply when the liquid sample is supplied to the sensor, and the sensor measuring device detects the change in the resistance value in the sensor to automatically start the measurement, whereby variations in the measurement results due to variations in the measurement start operations by users are avoided. Further, an adjustment chip having a constant resistance value, which chip is similar in shape to the above-described sensor, is formed, and when a measuring sensor and an adjustment sensor (adjustment chip) are loaded to the measuring device, the measuring device automatically distinguishes the measuring sensor from the adjustment sensor according to a difference in resistance values between these two sensors, thereby automatically adjusting, calibrating or examining the measuring device.
Among the adjustment chips, there are, for example, two types of chips as adjustment chips to be used by a patient himself as follows.
1. A correction chip for adjusting errors in analytical curves or the like, which occur due a lot change of materials, every time a patient buys sensors by a box.
2. A check chip for performing an operative validation of a measuring device itself, which is employed only when a patient buys a new device.
The above-mentioned materials denote components which may vary due to a lot change. For example, when the employed sensor comprises an enzyme electrode, there may be lot-to-lot variations in an enzyme or an electrode material, when the sensor comprises an ion selective electrode, there may be lot-to-lot variations in an ion selective film material or a metal foil used for the electrode, and when the sensor adopts optical detection, there may be lot-to-lot variations in a reagent ingredient or an optical element. Therefore, all sensor measuring devices employing sensors require adjustment chips suitable to the respective detection principles although the detection principles are different from each other.
However, both of the two adjustment chips, i.e., the correction chip and the check chip, are usually similar in shape to the measuring sensor used for the measurement. FIGS. 7(a) and (b) show plan views and side views illustrating a check chip and a correction chip according to prior art. For example, when taking, as an example, a correction chip 100 using a resistance value as a target of correction, as shown in FIGS. 7(a) and (b), this correction chip is generally constituted by a sensor body 10, an incorrect insertion preventing projection 102 to be a protrusion for preventing the sensor from being inserted into a measuring device while mistaking the inside of the sensor for the outside, and a convex-shaped structural characterizing portion 103 which is swelled because a resistor is buried therein. As shown in FIGS. 7(a) and (b), since the correction chip 100 and the check chip 110 are especially similar to each other in shape, these chips are easily confused with each other due to the similarity in the shape. Accordingly, when a visually handicapped person or a weak-sighted person uses the correction chip 100 or the check chip 110, the possibility that the two chips are erroneously used is very high.
The present invention is made to solve the problems and has an object to provide a check chip for performing an operative validation of a sensor measuring device, which can be easily distinguished from a correction chip for adjusting errors even by a visually handicapped user.
According to the present invention, there is provided a check chip which is installed on a measuring device employing an exclusively used sensor and checks operations of the measuring device itself, wherein the check chip is provided thereon with at least one structural characterizing portion which makes a user of the measuring device recognize a difference from a correction chip for correcting errors that occur with lot changes in the exclusively used sensor.
Therefore, it is possible to provide a check chip, in which a difference from the correction chip can be easily detected, so that it is possible to prevent confusion when using the check chip and the correction chip.
According to the present invention, in the check chip, the structural characterizing portion has a shape, such as a convex shape, which can be recognized by the user from touch, and is provided in a location where the user is considered to pick up the check chip.
Therefore, it is possible to provide a check chip, in which a difference from the correction chip can be detected with touch, so that even a visually handicapped person or a weak-sighted person can detect a difference from the correction chip.
According to the present invention, in the check chip, a difference between the check chip and the correction chip resides in a size of the structural characterizing portion, when the correction chip has the structural characterizing portion.
Therefore, it is possible to provide a check chip in which a difference between the check chip and the correction chip can be detected in the size of the structural characterizing portion with touch, and even a visually handicapped person or a weak-sighted person can easily detect the difference from the correction chip.
According to the present invention, in the check chip, the size of the structural characterizing portion provided on the check chip is larger than that of the structural characterizing portion provided on the correction chip.
Therefore, it is possible to provide a check chip in which a person can detect, with touch, that the structural characterizing portion of the check chip is larger than that of the correction chip, so as to detect the difference from the correction chip, whereby even a visually handicapped person or a weak-sighted person can be prevented from using the two chips with confusion. Further, the structural characterizing portion of the check chip, the usage frequency of which is lower than that of the correction chip, is enlarged, and therefore, manufacturing cost can be reduced.
According to the present invention, in the check chip, the size of the structural characterizing portion provided on the check chip is smaller than that of the structural characterizing portion provided on the correction chip.
Therefore, it is possible to provide a check chip in which a person can detect, with touch, that the structural characterizing portion of the check chip is smaller than that of the correction chip, so as to easily distinguish the difference from the correction chip, whereby it is possible to prevent a visually handicapped person or a weak-sighted person from using the two chips with confusion.
According to the present invention, the check chip is provided with the structural characterizing portion on the both sides of the check chip.
Therefore, it is possible to provide a check chip in which the difference between the check chip and the correction chip can be detected with touch, according to the mounted place of the structural characterizing portion, whereby the difference from the correction chip can be detected easily even by a visually handicapped person or a weak-sighted person.
According to the present invention, in the check chip, a difference between the check chip and the correction chip resides in a number of the structural characterizing portions.
Therefore, it is possible to provide a check chip in which the difference between the check chip and the correction chip can be detected with touch, according to the number of the structural characterizing portions, whereby the difference from the correction chip can be detected easily even by a visually handicapped person or a weak-sighted person.
According to the present invention, in the check chip, the number of the structural characterizing portions provided on the check chip is larger than that of the structural characterizing portions provided on the correction chip.
Therefore, it is possible to provide a check chip in which a person can detect, with touch, that the number of the structural characterizing portions of the check chip is larger than that of the structural characterizing portions of the correction chip, so as to easily detect the difference from the correction chip, whereby it is possible to prevent a visually handicapped person or a weak-sighted person from using the two chips with confusion. Further, the number of the structural characterizing portions of the check chip, the usage frequency of which is lower than that of the correction chip, is enlarged, and therefore, manufacturing cost can be reduced.
According to the present invention, in the check chip, the number of the structural characterizing portions provided on the check chip is smaller than that of the structural characterizing portions provided on the correction chip.
Therefore, it is possible to provide a check chip in which a person can detect, with touch, that the number of the structural characterizing portions of the check chip is smaller than that of the structural characterizing portions of the correction chip, so as to easily detect the difference from the correction chip, whereby it is possible to prevent a visually handicapped person or a weak-sighted person from using the two chips with confusion.
According to the present invention, in the check chip, a structural characterizing portion on an attention attracting character printed on an upside of the check chip, among plural structural characterizing portions provided on the check chip, has optical penetrability.
Therefore, it is possible to make the attention attracting character readable, even when the attention attracting character printed on the chip which indicates a type of the chip is hidden under the structural characterizing portion on the ground that the number of the structural characterizing portions is large, whereby even a person having a good sight who does not know a detection method according to the structural characterizing portions of the both chips can easily distinguish the two chips from each other.
According to the present invention, in the check chip, a difference between the check chip and the correction chip resides in the shape of the structural characterizing portion.
Therefore, it is possible to provide a check chip, in which a person can detect, with touch, the difference between the check chip and the correction chip according to the shape of the structural characterizing portions, whereby even a visually handicapped person or a weak-sighted person can easily distinguish the difference from the correction chip.